DUAL-FUNCTIONAL ZNO-EMBEDDED PVDF MEMBRANES FOR CONTINUOUS WATER PURIFICATION ANTIMICROBIAL ACTION

Abstract

Water purification methods based on membranes have attracted a lot of attention owing to their efficiency and scalable design, although the practicality of these technologies becomes greatly limited owing to the membrane fouling and biofilm formation. In spite of the numerous research works dedicated to the improvement of the water purification efficiency through the modification of the polymeric membranes using different nanomaterials like ZnO, most of the proposed systems only considered the performance during the relatively short-time period and were oriented at individual improvements (i.e., filtration, antifouling, or antimicrobial effects). The lack of information about long-term efficiency and synergy of such approaches hinders further development in the field. Dual-functional PVDF/ZnO nanocomposite membranes for water purification were synthesized in this work using phase inversion technique and were used for efficient and simultaneous removal of organic dyes and proteins in continuous mode, demonstrating excellent antifouling characteristics along with increased antimicrobial effect. Nanomaterials were proved to be very effective for improving both membrane hydrophilicity and permeability with decreasing the water contact angle from ~92° to ~68° and achieving the highest pure water flux of ~158 L m⁻² h⁻¹ at 1 wt%. In addition, significant antibacterial efficiency (>95%) against Gram negative and Gram-positive bacteria was accomplished based on the reactive oxygen species formation and Zn²⁺ ions release. Synergy of the physical filtration, adsorption, antibacterial and antifouling properties is illustrated by the created membrane, thus making it possible to obtain a promising strategy for developing advanced water-purification membranes.